Colorectal cancer is the third most frequent type of cancer in the world having an occurrence of about 1 million new cases every year. The incidents of cancer are considerably more frequent in the industrial part of the world.
Current techniques for mechanically performing anastomosis of hollow organs use circular mechanical staplers, which execute the connection of the tissue edges of the dissected hollow organ by metallic or plastic staples. A wide variety of surgical staplers have been developed for gastric, oesophageal and intestinal surgery. In performing surgical anastomotic stapling, generally two pieces of the hollow organ are joined by a ring of staples with a closed loopstapler. End to end anastomoses are generally performed by intraluminal surgical staplers that deliver a pair of staggered rings of staples. During this process, a circular knife blade is used to separate the tissue that is held within the circular ring. The separated tissue is then removed with the stapler to form a circular opening within the lumen along the stapling line.
A major issue regarding anastomosis healing is the blood circulation of the anastomosis during the healing process. Despite substantial development of surgical techniques during the last decades, morbidity and mortality after resections in the gastrointestinal tract, e.g. due to anastomotic leakage, remain as serious problems. Ischemia and inflammation, which are natural parts of the healing process, may cause leakage and secondary infection that may be fatal for the patient in the stapling area. Therefore, it has become common practice to relieve the pressure from the anastomosis by performing a deviating stoma, especially when the anastomosis is carried out in the lower part of colon and in rectum. By relieving pressure and faecal stream from the anastomosis during the healing process, the leakage incident may be reduced and fatal consequences of anastomotic dehiscence can be avoided. The inconvenience for the patient is obvious, since the patient must have a temporary stoma for a time period of about 3-6 months, and then has to undergo a second surgery in order to close the stoma. Unfortunately in many cases, the closure of the stoma cannot be reversed and the patient is forced to live with a permanent stoma leading to lower quality of life associated with increased costs.
Another problem arising from stapling of anastomosis is anastomotic stenosis. The critical area for healing is the contact area between the two ends of the hollow structure to be connected. The connection has to be liquid proof, and the cross section of the lumen should be as wide and flexible as the original lumen. The size of the stapler determines the size of the lumen and thus the contact area between the ends. Surgical staplers create a smaller and more rigid opening compared to the cross section of the original lumen due to the staples inside the hollow structure connecting the two ends thereof, i.e. a collar may be formed that may lead to stenosis. For solving this problem repeated need for dilatation is required.
Another disadvantage associated with mechanical staplers, is that there is no fast, simple and reliable method to control anastomotic insufficiency, which at late discovery can result in abdominal sepsis.
Furthermore, staplers require an incision in the intestine in order to insert the instrument into the bowel lumen. This additional incision increases the duration of the operation and the risks associated with surgery, e.g. secondary infections and anastomotic leakage.
The stapler itself is a critical link, since there are several severe problems connected with the use of mechanical staplers in surgical anastomotic stapling, such as anastomotic leakage and anastomotic stenosis. Other disadvantages are high consumption of time and expensive instruments for the performance.
U.S. Pat. No. 5,931,057 discloses a compression anastomosis assembly of interlocking members for use in achieving anastomosis of tubular organs. The assembly has a locking feature to prevent inadvertent disassembly of installed coupled members. One assembly member includes a cutting guide and a cutting ring. There may be difficulties to uniformly arrange the tubular organ into the assembly at installation, since two sheets of the tubular organ are overlapping each other at arrangement between two members of the assembly, which poses a risk for leakage.